 | This article needs additional citations for verification .(June 2017) |
| Eimeria tenella | |
|---|---|
 | |
| Eimeria tenella | |
Scientific classification  | |
| Clade: | SAR |
| Infrakingdom: | Alveolata |
| Phylum: | Apicomplexa |
| Class: | Conoidasida |
| Order: | Eucoccidiorida |
| Family: | Eimeriidae |
| Genus: | Eimeria |
| Species: | E. tenella |
| Binomial name | |
| Eimeria tenella (Tyzzer, 1929) | |
Eimeria tenella is a species of Eimeria that causes hemorrhagic cecal coccidiosis in young poultry. [1] It is found worldwide. [1]
This species has a monoxenous life cycle with the only definitive host as chickens; it is extremely host-specific. Acquired via fecal contamination of food and water (oral-fecal route), it undergoes endogenous merogony in the crypts of Lieberkuhn (intestinal ceca of chicken) and gametogony in epithelial cells of the small intestines. Fusion of microgamete and macrogamete forms results in unsporulated zygotes, which are released with feces of chicken. The zygote sporulates after one to five days, and becomes infective.
Diagnosis is based on finding oocysts in feces. While no effective treatment exists, the rate of infection can be reduced via prophylactics, anticoccidial drugs and vaccination of baby chicks.
Eimeria tenella has a monogenetic life cycle, that is, the life cycle involves a single host. [2] Various stages of its complicated life cycle may conveniently be described under two phases, asexual cycle or schizogony and sexual cycle involving gametogony. Much of life cycle is intracellular. It is one of seven protozoan parasites that cause avian coccidiosis in poultry.
The unsporulated oocyst is shed from an infected bird in the feces. This exposure to air and moisture triggers meiosis and cell division. After 9–12 hours of sporulation (asexual reproduction by the production and release of spores) eight haploid sporozoites are formed. It has completed the sporulation stage after about 24 hours and can now infect a new host.
The chicken ingests the sporozoite where it is stripped of its oocyst wall by abrasion in the gizzard and breakdown in the lumen of the small intestine. The sporozoite then migrates to its preferred site of development (the caeca in the case of Eimeria tenella) and invades the villus enterocyte. It then migrates to the crypt of the villus where it will complete development. There are two generations of schizonts and merozoites which are morphologically distinguishable. The sporozoites undergo two waves of schizogeny (asexual reproduction) in the crypts and produce many first and second generation merozoites. These merozoites can invade locally and reproduce themselves to produce a smaller variety of schizonts. The sporozoites are then shed in the feces and the process begins again.
The beginning of complex life cycle of Eimeria tenella may be taken to be initiated by infection of epithelial cells of host cecum by sporozoites. The infected fowl passes out oocysts or zygocysts with fecal matter. When their oocysts are swallowed by a new or healthy bird, its gizzard and digestive juices dissolve the cystwall and release sporozoites which enter the host epithelial cells. Within the epithelial cells, the sporozoites grow in size and multiply by schizogony.
It is the earliest intracellular stage of parasite. It is elongated, slightly curved, microscopic unicellular organism with one end pointed and the other end blunt. The pellicle, forming external envelope, contains longitudinally arranged contractile microtubules which help in wriggling movements of organism. Cytoplasm includes a vesicular nucleus, a mitochondrion, golgi bodies, endoplasmic reticulum, ribosomes, lysosomes and vacuoles containing reserve food, etc. Penetration of sporozoite into host epithelial cell is facilitated by the lytic secretion stored in roptries of parasite. The measurement of body is as 19.5–25 by 16.5–23 micrometer.
The Apicomplexa are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure. The organelle is an adaptation that the apicomplexan applies in penetration of a host cell.
Isosporiasis, also known as cystoisosporiasis, is a human intestinal disease caused by the parasite Cystoisospora belli. It is found worldwide, especially in tropical and subtropical areas. Infection often occurs in immuno-compromised individuals, notably AIDS patients, and outbreaks have been reported in institutionalized groups in the United States. The first documented case was in 1915. It is usually spread indirectly, normally through contaminated food or water (CDC.gov).
Coccidia (Coccidiasina) are a subclass of microscopic, spore-forming, single-celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida. As obligate intracellular parasites, they must live and reproduce within an animal cell. Coccidian parasites infect the intestinal tracts of animals, and are the largest group of apicomplexan protozoa.
Plasmodium vivax is a protozoal parasite and a human pathogen. This parasite is the most frequent and widely distributed cause of recurring malaria. Although it is less virulent than Plasmodium falciparum, the deadliest of the five human malaria parasites, P. vivax malaria infections can lead to severe disease and death, often due to splenomegaly. P. vivax is carried by the female Anopheles mosquito; the males do not bite.
Eimeria is a genus of apicomplexan parasites that includes various species capable of causing the disease coccidiosis in animals such as cattle, poultry, dogs, cats, and smaller ruminants including sheep and goats. Eimeria species are considered to be monoxenous because the life cycle is completed within a single host, and stenoxenous because they tend to be host specific, although a number of exceptions have been identified. Species of this genus infect a wide variety of hosts. Thirty-one species are known to occur in bats (Chiroptera), two in turtles, and 130 named species infect fish. Two species infect seals. Five species infect llamas and alpacas: E. alpacae, E. ivitaensis, E. lamae, E. macusaniensis, and E. punonensis. A number of species infect rodents, including E. couesii, E. kinsellai, E. palustris, E. ojastii and E. oryzomysi. Others infect poultry, rabbits and cattle. For full species list, see below.
Eimeria stiedae is a species of Eimeria that causes hepatic coccidiosis in rabbits. It was observed for the first time by Antonie van Leeuwenhoek in 1674.
Leucocytozoon is a genus of parasitic alveolates belonging to the phylum Apicomplexa.
Megaloschizonts are large schizonts that produce extremely high numbers of merozoites. They are found in various species of the Phylum Apicomplexa. The Apicomplexa phylum contains several parasitic protozoans. They have a very complex life cycle that includes several stages. Megaloschizonts and the smaller schizonts are the part of the life cycle that takes place inside the infected host organism and operates as an asexually reproductive cell. Megaloschizonts appear as grey-white nodules found in the smooth muscle of major organs, such as the heart, liver, lung or spleen.
Cryptosporidium hominis, along with Cryptosporidium parvum, is among the medically important Cryptosporidium species. It is an obligate parasite of humans that can colonize the gastrointestinal tract resulting in the gastroenteritis and diarrhea characteristic of cryptosporidiosis. Unlike C. parvum, which has a rather broad host range, C. hominis is almost exclusively a parasite of humans. As a result, C. hominis has a low zoonotic potential compared to C. parvum. It is spread through the fecal-oral route usually by drinking water contaminated with oocyst laden feces. There are many exposure risks that people can encounter in affected areas of the world. Cryptosporidium infections are large contributors of child death and illness in heavily affected areas, yet low importance has been placed on both identifying the species and finding more treatment options outside of nitazoxanide for children and AIDS patients.
Karyolysus is a genus of coccidia. With the exception of K. sonomae whose vertebrate host is the yellow-legged frog, species in this genus only infect lizards of the genus Lacerta.
Apicomplexans, a group of intracellular parasites, have life cycle stages that allow them to survive the wide variety of environments they are exposed to during their complex life cycle. Each stage in the life cycle of an apicomplexan organism is typified by a cellular variety with a distinct morphology and biochemistry.
Dactylosoma is a genus of parasitic alveolates of the phylum Apicomplexia.
The genus Schellackia comprises obligate unicellular eukaryotic parasites within the phylum Apicomplexa, and infects numerous species of lizards and amphibians worldwide. Schellackia is transmitted via insect vectors, primarily mites and mosquitoes, which take up the parasite in blood meals. These vectors then subsequently infect reptilian and amphibian which consume the infected insects. The parasites deform erythrocytes of the host into crescents, and can be visualised using a blood smear.
Atoxoplasma is a genus of parasitic alveolates in the phylum Apicomplexa. The species in this genus infect birds. They are spread by the orofaecal route.
Cystoisospora belli, previously known as Isospora belli, is a parasite that causes an intestinal disease known as cystoisosporiasis. This protozoan parasite is opportunistic in immune suppressed human hosts. It primarily exists in the epithelial cells of the small intestine, and develops in the cell cytoplasm. The distribution of this coccidian parasite is cosmopolitan, but is mainly found in tropical and subtropical areas of the world such as the Caribbean, Central and S. America, India, Africa, and S.E. Asia. In the U.S., it is usually associated with HIV infection and institutional living.
Cystoisospora canis, previously known as Isospora canis, is a microscopic, coccidian parasite that causes an intestinal tract infection in dogs. The intestinal tract infection is coccidiosis caused by a protozoa called coccidia.
Growell India is a multinational feed additive company headquartered in Pune, Maharashtra, India. Growell India manufactures and exports phytogenic feed additives for livestock. The company is a pioneer in phytogenic feed additives and has established a strong presence worldwide since its inception in 1995.
Sarcocystis neurona is primarily a neural parasite of horses and its management is of concern in veterinarian medicine. The protozoan Sarcocystis neurona is a protozoan of single celled character and belongs to the family, Sarcocystidae, a group called coccidia. The protozoan, S. neurona, is a member of the genus Sarcocystis, and is most commonly associated with equine protozoal myeloencephalitis (EPM). The protozoan, S. neurona, can be easily cultivated and genetically manipulated, hence its common use as a model to study numerous aspects of cell biology.
Eimeria zuernii is a species of the parasite Eimeria that causes diarrheic disease known as eimeriosis in cattle, and mainly affects younger animals. The disease is also commonly referred to as coccidiosis. The parasite can be found in cattle around the globe.
Eimeria bovis is a paraiste belonging to the genus Eimeria and is found globally. The pathogen can cause a diarrheic disease in cattle referred to as either eimeriosis or coccidiosis. The infection predominantly cause disease in younger animals.
